Double toggle finger holder



Aug. 19, 1941 A- E. DRlSSNER DOUBLE TOGGLE FINGER HOLDER Filed Dec. 27, 1939 2 Sheets-Sheet 1 ATTORNEY INVENTQR 1941- A. E. DRISSNER DOUBLE TOGGLE FINGER HOLDER Filed Dec. 27, 1939 2 Sheets-Sheet 2 ATTORNEY Patented Aug. 19, 1941 DOUBLE TOGGLE FINGER HOLDER Alfred E. Drissner, Cleveland, Ohio, assignor to a The National Acme Company, Cleveland, Ohio,

a corporation of Ohio Application December 27, 1939, Serial No. 311,107 '1 Claims. (01. 279-1) This invention relates to finger holders for spindles and is particularly adapted for use with automatically operative chucks or collets and is a continuation-in-part of the contemporaneously pending application, Serial Number 304,319, filed November '14, 1939, being an improvement upon that shown and described in my contemporaneously pending application Serial Number 257,604, filed February 21. 1939.

The object of the invention is the provision of improved finger holder mechanism particularly designed for use with single and multiple spindle automatic 'screw machines and which, like that shown in my said prior application, is capable of exerting great pressure on the chucks or collets to close and maintain themclosed onto the stock during tooling operations with but comparatively slight pressure on and movement of. the fingers but, in addition thereto, is "capable of handling bar stock of greater diametrical variation because of the greater longitudinal movement of the collet. This longer movement urges the collet farther out of the spindle nose and away from the tapered seat, thereby allowing the colletjaws to spring radially outwardly a greater amount than if the collet movement were only one-half this amount as is the case with finger holders of my prior improvement when used with the same amount of sleeve movement and these advantages are obtained while maintaining the compactness of the unit and the minimizing of the sleeve movement, all of which are important in the construction of spindles for bar machines.

An object of the present invention, therefore, 35

In the drawings accompanying and forming a 40 part of this specification, Fig. 1 is a longitudinal sectional view of this improved finger holder illustrating the collet in open position.

Fig. 2 is an enlarged sectional view taken on line 22 of Fig. l.

Fig. 3 is an enlarged detail view oi the toggle levers for operating the collet, and

Fig. Q is an enlarged detail of the cam for operating the toggle levers.

Similar characters of reference indicate cor- 60 of the collet tube and also equalizing the strain responding parts in the several views.

Before explaining in detail the present improvement and its mode of operation, I desire to have it understood that the invention is not rangement of parts illustrated in the accompanying drawings since the-invention is capable of other embodiments, and that the phraseology employed is for the purpose of description and not of limitation.

In the present instance, a tubular spindle of a. multiple spindle machine of the bar stock type has been illustrated and when applied to this type of machine, the finger holders are located on the rear end of the tubular spindle 2 carried by the indexible work spindle carrier in the usual manner.

Within the spindle 2 is located the collet tube 3 and interiorly of the collet tube is the feed or pusher tube 4. The front end of the collet tubet is provided with the usualchuck or collet 5 suitably secured to the collet tube and the feed follet 6 is suitably secured to the front end of the feed tube 4.

A sleeve or body member I is suitably secured to-the spindle 2 for rotation therewith and the rear end of this sleeve is provided with a ring 8 secured to the sleeve 1 by pins 9. This ring 8 is provided with cylindrical sockets It for the 2s reception of the enlarged knuckle-formed ends 80 and is provided with suitable bushings It to prevent scoring of the spindle upon the sliding movement of this ring.

The ring l5 likewise has cylindrical sockets I'I similar to those of its companion ring 8 for the reception of enlarged knuckle-formed ends it of the other toggle links 19 and these sockets are in line with the sockets 10 of the ring 8. Suitable means is provided to maintain the rings 8 and I! in alignment.

The toggle links or levers l2 and I9 each doubleended or of integral U-shape having their overlapping ends pivotally connected by a pin 20' and on this pin is mounted a roller 2| located within the overlapping sides of the toggle links.

Both the toggle links or levers of each toggle are or the same length, each having substantially one-half thereof formed with an enlarged knuckle end thus enabling the use of a double toggle in a small space while increasing the movement of the parts.

Between the nut 14 and the ring it are arranged thrust washers 22 and cup springs 23 for cushioning and taking up the thrust of the limited to the details of construction and ar- 88 parts.

The shifting of the ring member I! will cause the nut H to move "rearward to draw the collet tube 3 inwardly to close the collet onto the work to be gripped as is usual in machines of this type.

A sliding sleeve or spool 24 having :an annular recess 25 for the engagement of a suitable shoe (not shown) is adapted to shift a tapered cam member 26 over the roller when the sleeve is shifted longitudinally by means of the usual mechanism on machines of this kind. This shiftable cam 26 riding over the roller 2| depresses the roller and spreads the toggle members l2 and I! to effect rearward movement of the ring I5 and collet tube 3 to close the chuck onto the work. v Upon shifting the sleeve 24 and its cam 26 in the opposite direction, the pressure of the cam 26 on the roller 2| is released and the spring action of the collet 5 causes the collet tube 3 to be shifted forwardly, thus returning the toggle members to their r'eleased position, in which position as will be seen in Fig. 1, the distance between the opposing faces of the socketed mem-' bers 8 and I 5 substantially coincides with the diameter of the roll, thereby permitting the use of this toggle in a. small compact space without affecting theefliciency thereof and this result is obtained by reason of the fact that the diameter of the roll, length of the levers and diameters 'of the cooperating enlarged lever ends and sockets. wherein these sockets receive more than onehalf of the enlarged ends, are all so proportioned and constructed relative one to another that the relatively shiftable members 8 and [5 may very closely approach each other and yet have considerable longitudinal movement to exert great pressure on the chucks or collets with but slight movement of the operating sleeve as hereinbefore described.

The rings 8 and i5 are provided with suitable slots 21 in alignment with each other to permit the cam 26 to slide freely therein and maintain the parts in proper position at all times and thus reducing the diameter of this finger holding more compact space.

Any suitable number of these toggle units or vention beyond the terms of the several claims 1 or the requirements of the prior art.

Having thus explained the nature of my invention and described a way of constructing and using the same, although without attempting to set forth all of the forms in which it may be made or all of the modes of its use, I claim:

1. A finger holder for 'a chuck or collet of a rotary spindle automatic screw machine and comprising a double toggle consisting of a pair of toggle levers having overlapping inner ends,

a roller at the juncture thereof, each lever having an enlarged cylindrical end, a pair of relatively .shiftable members having enlarged cylindrical sockets for the reception of the cylindrical ends of the levers, and sliding cam means cooperating with the roller for depressing the roller to spread the toggle, the diameter of the roller, length of the levers and diameters of the cooperating lever ends and'socketsso proportioned and constructed relative one to the other that when the roller is released and the socketed members are relatively shifted toward each other, the distance between the opposing faces of said socketed members will substantially coincide with the diameter of the roller thereby permitting the use of this toggle in a small compact space the cylindrical ends of the levers, and sliding cam means shiftable in the peripheral slots of the relatively shiftable members-thereby reducing the diameter of the finger holder and cooperating with the roller for depressing the roller to spread the toggle, the diameter of the roller, length of the levers and diameters of the cooperating lever ends and sockets so proportioned and constructed relative one' to another that when the roller is released and the socketed members are relatively shifted toward each other,

the distancebetween the opposing faces of said socketed members will substantially coincide with the diameter of the roller thereby permitting the use of this toggle in a small compact space without affecting the efiiciency thereof.

3. The finger holder of claim 1 in which the relatively shiftable members are ring-shaped and a plurality of sets of double toggles are spaced therearound and in which spring cushioning means is provided for the shiftable ring.

4. The finger holder of claim 1 in which the diameters of the sockets of the relatively shiftable members are such as to receive more than half of the enlarged ends of thetoggle levers.

5. The finger holder of claim 1 in which the toggle levers are of substantially the same length and substantially one-half of each lever comprises the enlarged end thereof. v

6. The finger holder of claim 1 in which the ,diameters of the'sockets of thei'elatively shiftable members are such as to receive more than half of the enlarged ends of the toggle levers and each of which-toggle levers is ,of an integral U-shaped construction and of substantially the same length and substantially one-half of each lever comprises the enlarged end thereof.

ALFR ED E. DRISSNER. 

